1. Field of the Invention
The present invention relates to a touch panel.
2. Description of the Related Art
Patent Document 1 discloses a touch panel in which assistance electrodes, each being formed in a line shape, are provided in parallel with four electrodes, to be electrically connected to the four electrodes via an ITO pattern, respectively. In this technique, the assistance electrodes are spaced apart from each other so as to prevent them from being electrically connected with each other. The touch panel further includes connecting lines that connect the four electrodes to a control unit at corners of a rectangular ring shape structure formed by the four electrodes, and connecting lines that connect the assistance electrodes to the control unit from both sides of each of the assistance electrodes.
Patent Document 2 discloses a touch sensor including a substrate including a resistance touching area, a pair of electrodes electrically connected to the touching area, a cover sheet that includes a conductive layer which is formed on and in the vicinity of the electrodes to face the touching area, plural band portions provided at the outside peripheral of the touching area and having a resistance value between that of the electrodes and that of the touching area to provide a transition between the low-resistance electrodes and the high-resistance touching area.
Patent Document 3 discloses a touch panel including a resistance film, a common electrode to provide a voltage to the resistance film and a voltage supplying unit that supplies the voltage to the common electrode, where an electric potential distribution is generated by supplying the voltage from the voltage supplying unit to the common electrode and from the common electrode to the resistance film. In this touch panel, a touched position is detected by detecting the electric potential of the resistance film at the touched position. The touch panel further includes an insulating layer which is provided between the common electrode and the resistance film.
Unfortunately, for the conventional touch panel, distortion of an electric potential distribution is generated when applying voltages to the electrodes to detect the touched position.
If the distortion of an electric potential distribution is generated, the touched position cannot be accurately detected.